Розгадка срібного ключа (англ.)

The first volume of Scotland Yard Book by the English writer Edgar Wallace (1875-1932) included the thriller novel The Clue of the Silver Key.  In the story, Surefoot Smith of Scotland Yard is called in to investigate when petty thief Tom Tickler is murdered and left in a cab with ?100 in his pocket. His discovery eventually leads to the mysterious businessman Washington Wirth.